STATISTICS OF CONDUCTANCE FLUCTUATIONS IN QUANTUM DOTS

Recent experiments measuring both the statistical and spectral properties of ballistic conductance fluctuations in GaAs quantum dots are described. Shape distortion using a small “pin” gate provides a novel means of generating conductance fluctuations, and also allows fluctuation statistics to be measured at fixed magnetic field. Changes in both the mean and the variance of conductance fluctuations are seen upon breaking time-reversal symmetry with an applied magnetic field. The phase-breaking time T φ(T) in the dot is measured using the power spectrum of conductance fluctuations and is compared to recent 0-D theory.